Transport system, mover, control apparatus, and control method

ABSTRACT

A transport system includes: a mover having a first magnet group arranged in parallel to a first direction and a second magnet group arranged in parallel to a second direction crossing the first direction; and a plurality of coils arranged in parallel to the first direction so as to be able to face the first magnet group and the second magnet group, and the mover is able to move in the first direction along the plurality of coils by electromagnetic force received by the first magnetic group from the plurality of coils while an attitude of the mover is controlled by electromagnetic force received by the first magnetic group or the second magnetic group from the plurality of coils.

This application is a continuation of U.S. application Ser. No.16/531,684, filed on Aug. 5, 2019.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a transport system, a mover, a controlapparatus, and a control method.

Description of the Related Art

In general, a transport system is used in production lines,semiconductor exposure apparatuses, or the like for assemblingindustrial products. In particular, a transport system in a productionline transports workpieces such as components between a plurality ofstations within a production line or between production lines that arefactory-automated or may be used as a transport apparatus in a processapparatus. As a transport system, a transport system with a movablemagnet type linear motor has already been proposed.

A transport system with a movable magnet type linear motor is formed byusing a guide apparatus such as a linear guide involving mechanicalcontact. In a transport system using a guide apparatus such as a linearguide, however, there is a problem of degeneration of productivitycaused by a contamination substance issued from a sliding portion of thelinear guide, for example, scrapers of a rail or a bearing, a lubricantoil, a volatilized component thereof, or the like. Further, there is aproblem of increased friction of a sliding portion during high speedtransportation, which reduces the life of the linear guide.

Accordingly, Japanese Patent Application Laid-Open No. 2015-230927 andJapanese Patent Application Laid-Open No. 2016-532308 disclosenon-contact magnetic levitation type motion apparatus or transportapparatus with no sliding portion as a guide. In a motion apparatusdisclosed in Japanese Patent Application Laid-Open No. 2015-230927,seven lines of linear motors are installed for controllingtransportation and attitude of a mover. Further, also in the transportapparatus disclosed in Japanese Patent Application Laid-Open No.2016-532308, six lines of electromagnets for levitation, electromagnetsfor guiding, and electromagnets for propulsion are installed.

In the apparatuses disclosed in Japanese Patent Application Laid-OpenNo. 2015-230927 and Japanese Patent Application Laid-Open No.2016-532308, however, a large number of lines of installed linear motorsor electromagnets makes it difficult to avoid increase in size of asystem.

SUMMARY OF THE INVENTION

The present invention intends to provide a transport system, a mover, acontrol apparatus, and a control method that can transport a movercontactlessly while controlling the attitude of the mover withoutinvolving increase in size of a system configuration.

According to one aspect of the present invention, provided is atransport system including: a mover having a first magnet group arrangedin parallel to a first direction and a second magnet group arranged inparallel to a second direction crossing the first direction; and aplurality of coils arranged in parallel to the first direction so as tobe able to face the first magnet group and the second magnet group, andthe mover is able to move in the first direction along the plurality ofcoils by electromagnetic force received by the first magnetic group fromthe plurality of coils while an attitude of the mover is controlled byelectromagnetic force received by the first magnetic group or the secondmagnetic group from the plurality of coils.

According to another aspect of the present invention, provided is amover including: a first magnet group arranged in parallel to a firstdirection; and a second magnet group arranged in parallel to a directioncrossing the first direction, and the mover is able to move in the firstdirection along a plurality of coils by electromagnetic force receivedby the first magnetic group from the plurality of coils while anattitude of the mover is controlled by electromagnetic force received bythe first magnetic group or the second magnetic group from the pluralityof coils, and the plurality of coils are arranged in parallel to thefirst direction so as to be able to face the first magnet group and thesecond magnet group.

According to yet another aspect of the present invention, provided is acontrol apparatus that controls a mover having a first magnet grouparranged in parallel to a first direction and a second magnet grouparranged in parallel to a direction crossing the first direction,wherein the mover is able to move in the first direction along aplurality of coils by electromagnetic force received by the firstmagnetic group from the plurality of coils while an attitude of themover is controlled by electromagnetic force received by the firstmagnetic group or the second magnetic group from the plurality of coils,and the plurality of coils are arranged in parallel to the firstdirection so as to be able to face the first magnet group and the secondmagnet group. The control apparatus includes: a transport control unitthat controls transportation of the mover in the first direction bycontrolling electromagnetic force received by the first magnet groupfrom the plurality of coils; and an attitude control unit that controlsan attitude of the mover by controlling electromagnetic force receivedby the first magnetic group or the second magnetic group from theplurality of coils.

According to still another aspect of the present invention, provided isa control method that controls a mover having a first magnet grouparranged in parallel to a first direction and a second magnet grouparranged in parallel to a direction crossing the first direction,wherein the mover is able to move in the first direction along aplurality of coils by electromagnetic force received by the firstmagnetic group from the plurality of coils while an attitude of themover is controlled by electromagnetic force received by the firstmagnetic group or the second magnetic group from the plurality of coils,and the plurality of coils are arranged in parallel to the firstdirection so as to be able to face the first magnet group and the secondmagnet group. The control method includes: controlling transportation ofthe mover in the first direction by controlling electromagnetic forcereceived by the first magnet group from the plurality of coils; andcontrolling an attitude of the mover by controlling electromagneticforce received by the first magnetic group or the second magnetic groupfrom the plurality of coils.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A a schematic diagram illustrating the entire configuration of atransport system including a mover and a stator according to a firstembodiment.

FIG. 1B is a schematic diagram illustrating the entire configuration ofthe transport system according to the first embodiment.

FIG. 2 is a schematic diagram illustrating the mover and the stator inthe transport system according to the first embodiment.

FIG. 3 is a schematic diagram illustrating a coil of the stator in thetransport system according to the first embodiment.

FIG. 4 is a schematic diagram illustrating a control system thatcontrols the transport system according to the first embodiment.

FIG. 5 is a schematic diagram illustrating an attitude control method ofthe mover in the transport system according to the first embodiment.

FIG. 6 is a schematic diagram illustrating a process by using a moverposition calculation function in the transport system according to thefirst embodiment.

FIG. 7 is a schematic diagram illustrating a process by using a moverattitude calculation function in the transport system according to thefirst embodiment.

FIG. 8A is a schematic diagram illustrating a process by using the moverattitude calculation function in the transport system according to thefirst embodiment.

FIG. 8B is a schematic diagram illustrating a process by using the moverattitude calculation function in the transport system according to thefirst embodiment.

FIG. 9 is a schematic diagram illustrating a method of applying force inthe X-direction and the Y-direction independently to permanent magnetsof the mover in the transport system according to the first embodiment.

FIG. 10 is a schematic diagram illustrating a mover in a transportsystem according to a second embodiment.

FIG. 11 is a schematic diagram illustrating a mover and a stator in atransport system according to the second embodiment.

FIG. 12 is a schematic diagram illustrating a mover and a stator in atransport system according to a third embodiment.

FIG. 13 is a schematic diagram illustrating a mover in a transportsystem according to the third embodiment.

FIG. 14A is a schematic diagram illustrating a mover in a transportsystem according to a first modified example of the third embodiment.

FIG. 14B is a schematic diagram illustrating a mover in a transportsystem according to a second modified example of the third embodiment.

FIG. 14C is a schematic diagram illustrating a mover in a transportsystem according to a third modified example of the third embodiment.

FIG. 14D is a schematic diagram illustrating a mover in a transportsystem according to a fourth modified example of the third embodiment.

FIG. 15 is a schematic diagram illustrating a mover and a stator in atransport system according to a fourth embodiment.

FIG. 16 is a schematic diagram illustrating a mover and a stator in atransport system according to the fourth embodiment.

DESCRIPTION OF THE EMBODIMENTS First Embodiment

A first embodiment of the present invention will be described below withreference to the drawings, namely, by using FIG. 1A to FIG. 9.

First, the entire configuration of a transport system according to thepresent embodiment will be described by using FIG. 1A and FIG. 1B. FIG.1A and FIG. 1B are schematic diagrams illustrating the entireconfiguration of the transport system including a mover 101 and a stator201 according to the present embodiment. Note that FIG. 1A and FIG. 1Billustrate extracted primary portions of the mover 101 and the stator201. Further, FIG. 1A is a diagram of the mover 101 when viewed from theZ-direction described later, and FIG. 1B is a diagram of the mover 101when viewed from the Y-direction described later.

As illustrated in FIG. 1A and FIG. 1B, a transport system 1 according tothe present embodiment has the mover 101 forming a truck, a slider, or acarriage and the stator 201 forming a transport path. The transportsystem 1 is a transport system with a movable magnet type linear motor(a moving permanent magnet type linear motor, a movable field magnettype linear motor). Furthermore, the transport system 1 is configured asa magnetic levitation type transport system that has no guide apparatussuch as a linear guide and transports the mover 101 contactlessly abovethe stator 201.

The transport system 1 transports a workpiece 102 on the mover 101 to aprocess apparatus that performs a processing operation on the workpiece102 by transporting the mover 101 by the stator 201, for example. Notethat, while FIG. 1A and FIG. 1B illustrate a single mover 101 for thestator 201, the number of movers 101 is not limited thereto. In thetransport system 1, a plurality of movers 101 may be transported abovethe stator 201.

Here, coordinate axes, directions, and the like used in the descriptionbelow are defined. First, the X-axis is taken along the horizontaldirection, which is a transport direction of the mover 101, and thetransport direction of the mover 101 is defined as the X-direction.Further, the Z-axis is taken along the vertical direction, which is adirection perpendicular to the X-direction, and the vertical directionis defined as the Z-direction. Further, the Y-axis is taken along adirection perpendicular to the X-direction and the Z-direction, and adirection perpendicular to the X-direction and the Z-direction isdefined as the Y direction. Moreover, rotation about the X-axis isdenoted as Wx, rotation about the Y-axis is denoted as Wy, and rotationabout the Z-axis is denoted as Wz. Further, a symbol “*” is used as asymbol for multiplication. Further, the center of the mover 101 isdenoted as the origin O, the positive (+) side of the Y-axis is denotedas an R-side, and the negative (−) side of the Y-axis is denoted as anL-side. Note that, while the transport direction of the mover 101 is notnecessarily required to be the horizontal direction, also in such acase, the transportation direction may be defined as the X-direction,and the Y-direction and the Z-direction may be defined in a similarmanner.

Next, the mover 101 that is a transport object in the transport system 1according to the present embodiment will be described by using FIG. 1A,FIG. 1B, and FIG. 2. FIG. 2 is a schematic diagram illustrating themover 101 and the stator 201 in the transport system 1 according to thepresent embodiment. Note that FIG. 2 is a diagram of the mover 101 andthe stator 201 when viewed from the X-direction. Further, the left halfpart of FIG. 2 illustrates a cross section (A) taken along a line(A)-(A) of FIG. 1B. Further, the right half part of FIG. 2 illustrates across section (B) taken along a line (B)-(B) of FIG. 1B.

As illustrated in FIG. 1A, FIG. 1B, and FIG. 2, the mover 101 haspermanent magnets 103 aR, 103 bR, 103 cR, 103 dR, 103 aL, 103 bL, 103cL, and 103 dL as permanent magnets 103.

The permanent magnets 103 are arranged and attached to both side facesof the mover 101 parallel to the X-direction. Specifically, thepermanent magnets 103 aR, 103 bR, 103 cR, and 103 dR are attached on aside face on the R-side of the mover 101. Further, the permanent magnets103 aL, 103 bL, 103 cL, and 103 dL are attached on a side face on theL-side of the mover 101. Note that, hereafter, the permanent magnets ofthe mover 101 are simply denoted as “permanent magnet(s) 103” as long asthey are not required to be distinguished in particular. Further, wheneach permanent magnet 103 is required to be identified individuallywhile the R-side and the L-side are not required to be distinguished,each permanent magnet 103 is individually identified by using areference in which R or L is removed from the tail of a referencecorresponding to each permanent magnet 103 and the reference charactersup to a small-letter alphabet as an identifier are left. In this case,“permanent magnet 103 a”, “permanent magnet 103 b”, “permanent magnet103 c”, or “permanent magnet 103 d” is denoted to individually identifyeach permanent magnet 103.

The permanent magnets 103 aR and 103 dR are attached to one end and theother end in the X-direction on the side face on the R-side parallel tothe X-direction of the mover 101. The permanent magnet 103 bR and 103 cRare attached between the permanent magnets 103 aR and 103 dR on the sideface on the R-side of the mover 101. The permanent magnets 103 aR, 103bR, 103 cR, and 103 dR are arranged at the equal pitch in theX-direction, for example. Further, the permanent magnets 103 aR, 103 bR,103 cR, and 103 dR are arranged such that respective centers thereof arealigned straight in parallel to the X-direction running the center ofthe side face on the R-side of the mover 101, for example.

The permanent magnets 103 aL and 103 dL are attached to one end and theother end in the X-direction on the side face on the L-side parallel tothe X-direction of the mover 101. The permanent magnet 103 bL and 103 cLare attached between the permanent magnets 103 aL and 103 dL on the sideface on the L-side of the mover 101. The permanent magnets 103 aL, 103bL, 103 cL, and 103 dL are arranged at the equal pitch in theX-direction, for example. Further, the permanent magnets 103 aL, 103 bL,103 cL, and 103 dL are arranged such that respective centers thereof arealigned straight in parallel to the X-direction running the center ofthe side face on the L-side of the mover 101, for example. Moreover, thepermanent magnets 103 aL, 103 bL, 103 cL, and 103 dL are arranged to thesame positions as the permanent magnets 103 aR, 103 bR, 103 cR, and 103dR in the X-direction, respectively.

The permanent magnets 103 a and 103 d are attached at positions that aredistant from the origin O, which is the center of the mover 101, by adistance ry on one side and the other side in the X-direction,respectively. The permanent magnets 103 a, 103 b, 103 c, and 103 d areattached at positions that are distant from the origin O by a distancerx in the Y-direction, respectively. The permanent magnets 103 c and 103b are attached to positions that are distant from the origin O by adistance rz on one side and the other side in the X-direction,respectively.

Each of the permanent magnets 103 aR, 103 dR, 103 aL, and 103 dL is aset of two permanent magnets arranged in parallel to the Z-direction.The permanent magnets 103 a and 103 d are formed, respectively, suchthat two permanent magnets are aligned in parallel to the Z-direction sothat the polarities of outer magnetic poles facing the stator 201 sideare different alternatingly. Note that the number of permanent magnetsarranged in parallel to the Z-direction forming the permanent magnets103 a and 103 d is not limited to two as long as it is plural. Further,the direction in which the permanent magnets forming the permanentmagnets 103 a and 103 d are arranged is not necessarily required to bethe Z-direction orthogonal to the X-direction that is the transportdirection but may be a direction crossing the X-direction. That is, thepermanent magnets 103 a and 103 d may be any magnet group formed of aplurality of permanent magnets arranged in parallel to a directioncrossing the X-direction such that the polarities of respective magneticpolarities are alternating.

On the other hand, each of the permanent magnets 103 bR, 103 cR, 103 bL,and 103 cL is a set of three permanent magnets arranged along theY-direction, respectively. The permanent magnets 103 b and 103 c areformed, respectively, such that three permanent magnets are aligned inparallel to the X-direction so that the polarities of outer magneticpoles facing the stator 201 side are different alternatingly. Note thatthe number of permanent magnets arranged in parallel to the X-directionforming the permanent magnets 103 b and 103 c is not limited to three aslong as it is plural. That is, the permanent magnets 103 b and 103 c maybe any magnet group formed of a plurality of permanent magnets arrangedin parallel to the X-direction such that the polarities of respectivemagnetic polarities are alternating.

Respective permanent magnets 103 are attached to yokes 107 provided onthe side faces on the R-side and the L-side of the mover 101. The yoke107 is made of a substance having a large magnetic permeability, forexample, an iron.

In such a way, a plurality of permanent magnets 103 are arranged to themover 101 symmetrically on the side faces on the R-side and the L-sidewith the center axis along the X-axis of the mover 101 being a symmetryaxis. The mover 101 on which the permanent magnets 103 are arranged isconfigured to be movable while the attitude is subjected to six-axiscontrol by electromagnetic force received by the permanent magnets 103from a plurality of coils 202 of the stator 201 as described later.

The mover 101 is movable in the X-direction along the plurality of coils202 arranged in two lines parallel to the X-direction. The mover 101 istransported with the workpiece 102 to be transported being placed on theupper face thereof. The mover 101 may have a holding mechanism thatholds the workpiece 102 such as a workpiece holder on the mover 101, forexample.

Next, the stator 201 in the transport system 1 according to the presentembodiment will be described by using FIG. 1A, FIG. 2, and FIG. 3. FIG.3 is a schematic diagram illustrating the coils 202 of the stator 201.Note that FIG. 3 is a diagram of the coils 202 when viewed from theY-direction.

The stator 201 has the plurality of coils 202 arranged in two linesparallel to the X-direction that is the transport direction of the mover101. The plurality of coils 202 are attached to the stator 201 so as toface the mover 101 from the R-side and the L-side, respectively. Thestator 201 extends in the X-direction, which is the transport direction,and forms a transport path of the mover 101.

The mover 101 transported on the stator 201 has a linear scale 104, aY-target 105, and Z-targets 106. The linear scale 104, the Y-target 105,and the Z-targets 106 are attached in parallel to the X-direction to thebottom of the mover 101, for example, respectively. The Z-targets 106are attached on both sides of the linear scale 104 and the Y-target 105,respectively.

As illustrated in FIG. 2, the stator 201 has the plurality of coils 202,a plurality of linear encoders 204, a plurality of Y-sensors 205, and aplurality of Z-sensors 206.

The plurality of coils 202 are arranged in two lines parallel to theX-direction and attached to the stator 201 so as to be able to face thepermanent magnets 103 on the side faces on the R-side and the L-side ofthe mover 101. The plurality of coils 202 arranged in one line on theR-side are arranged in parallel to the X-direction so as to be able toface the permanent magnets 103 aR, 103 bR, 103 cR, and 103 dR on theR-side of the mover 101. Further, the plurality of coils 202 arranged inone line on the L-side are arranged in parallel to the X-direction so asto be able to face the permanent magnets 103 aL, 103 bL, 103 cL, and 103dL on the L-side of the mover 101.

In the present embodiment, lines of the coils 202 on the R-side and theL-side of the mover 101 are arranged so as to be able to face thepermanent magnets 103 a and 103 d and the permanent magnets 103 b and103 c, respectively, in which arrangement directions of the plurality ofpermanent magnets are different between the permanent magnets 103 a and103 d and the permanent magnets 103 b and 103 c. Thus, force in thetransport direction and force in a direction different from thetransport direction can be applied to the mover 101 by using a fewerlines of coils 202 as described later, and therefore transport controland attitude control of the mover 101 can be realized.

In such a way, the plurality of coils 202 are attached along a directionin which the mover 101 is transported. The plurality of coils 202 arealigned at predetermined intervals in the X-direction. Further, each ofthe coils 202 is attached such that the center axis thereof is orientedin the Y-direction. Note that the coil 202 may be a coil with a core ormay be a coreless coil.

The plurality of coils 202 are configured to be current-controlled in aunit of three coils, for example. The unit in which current conductioncontrol is performed on the coils 202 is referred to as “coil unit 203”.When a current is conducted, the coil 202 can generate electromagneticforce with respect to the permanent magnets 103 of the mover 101 andapply force to the mover 101.

In FIG. 1A and FIG. 1B, the permanent magnets 103 a and 103 d are eachformed of a magnet group in which two permanent magnets are aligned inthe Z-direction. In contrast, each coil 202 is arranged such that thecenter in the Z-direction of two permanent magnets of the permanentmagnets 103 a and 103 d matches the center in the Z-direction of thecoil 202. Current conduction in the coils 202 facing the permanentmagnets 103 a and 103 d generates force in the Z-direction to thepermanent magnets 103 a and 103 d.

Further, the permanent magnets 103 b and 103 c are formed of a magnetgroup in which three permanent magnets are aligned in the X-direction.In contrast, current conduction in the coils 202 facing the permanentmagnets 103 b and 103 c generates force in the X-direction and theY-direction to the permanent magnets 103 b and 103 c.

The plurality of linear encoders 204 are attached to the stator 201parallel to the X-direction so as to be able to face the linear scale104 of the mover 101, respectively. Each of the linear encoders 204 candetect and output a relative position to the linear encoder 204 of themover 101 by reading the linear scale 104 attached to the mover 101.

The plurality of Y-sensors 205 are attached to the stator 201 parallelto the X-direction so as to be able to face the Y-target 105 of themover 101, respectively. Each of the Y-sensors 205 can detect and outputthe relative distance in the Y-direction between the Y-sensor 205 andthe Y-target 105 attached to the mover 101.

The plurality of Z-sensors 206 are attached to the stator 201 in twolines parallel to the X-direction so as to be able to face the Z-target106 of the mover 101, respectively. Each of the Z-sensors 206 can detectand output the relative distance in the Z-direction between the Z-sensor206 and the Z-target 106 attached to the mover 101.

Next, a control system that controls the transport system 1 according tothe present embodiment will be further described by using FIG. 4. FIG. 4is a schematic diagram illustrating a control system 3 that controls thetransport system 1 according to the present embodiment.

As illustrated in FIG. 4, the control system 3 has an integrationcontroller 301, coil controllers 302, and a sensor controller 304 andfunctions as a control apparatus that controls the transport system 1including the mover 101 and the stator 201. The coil controllers 302 arecommunicably connected to the integration controller 301. Further, thesensor controller 304 is communicably connected to the integrationcontroller 301.

A plurality of current controllers 303 are communicably connected to thecoil controllers 302. Each of the coil controllers 302 and the pluralityof current controllers 303 connected thereto are provided to thecorresponding line of two lines of the coils 202. The coil unit 203 isconnected to each of the current controllers 303. The current controller303 can control a current value of each of the coils 202 of theconnected coil unit 203.

The coil controller 302 instructs a target current value to each of theconnected current controllers 303. The current controller 303 controls acurrent amount of the connected coil 202.

The coil 202 and the current controller 303 are attached on both sidesin the X-direction in which the mover 101 is transported.

The plurality of linear encoders 204, the plurality of Y-sensors 205,and the plurality of Z-sensors 206 are communicably connected to thesensor controller 304.

The plurality of linear encoders 204 are attached to the stator 201 atintervals by which one of the linear encoders 204 can surely measure theposition of one mover 101 during transportation of the movers 101.Further, the plurality of Y-sensors 205 are attached to the stator 201at intervals by which two of the Y-sensors 205 can surely measure theY-target 105 of one mover 101. Further, the plurality of Z-sensors 206are attached to the stator 201 at intervals by which three of theZ-sensors 206 on the two lines can surely measure the Z-target 106 ofone mover 101.

The integration controller 301 determines a current instruction valueapplied to the plurality of coils 202 based on the output from thelinear encoders 204, the Y-sensors 205, and the Z-sensors 206 andtransmits the determined current instruction value to the coilcontrollers 302. The coil controller 302 instructs the currentcontroller 303 of a current value as described above based on thecurrent instruction value from the integration controller 301. Thereby,the integration controller 301 functions as a control apparatus,transports the mover 101 contactlessly above the stator 201, andcontrols the attitude of the transported mover 101 with respect to sixaxes.

An attitude control method of the mover 101 performed by the integrationcontroller 301 will be described below by using FIG. 5. FIG. 5 is aschematic diagram illustrating the attitude control method of the mover101 in the transport system 1 according to the present embodiment. FIG.5 illustrates the outline of the attitude control method of the mover101 in which the data flow thereof is mainly focused on. The integrationcontroller 301 performs a process using a mover position calculationfunction 401, a mover attitude calculation function 402, a moverattitude control function 403, and a coil current calculation function404, as described below. Thereby, the integration controller 301controls transportation of the mover 101 while controlling the attitudeof the mover 101 with respect to six axes. Note that, instead of theintegration controller 301, the coil controller 302 may be configured toperform the same process as that performed by the integration controller301.

First, the mover position calculation function 401 calculates the numberand the position of the movers 101 above the stator 201 forming thetransport path from measurement values from the plurality of linearencoders 204 and information on the attachment position thereof.Thereby, the mover position calculation function 401 updates moverposition information (X) and number information in mover information 406that is information on the movers 101. The mover position information(X) illustrates a position in the X-direction, which is the transportdirection of the movers 101 above the stator 201. The mover information406 is prepared for each mover 101 above the stator 201, as illustratedas POS-1, POS-2, . . . in FIG. 5, for example.

Next, the mover attitude calculation function 402 identifies theY-sensor 205 and the Z-sensor 206 that can measure each of the movers101 from the mover position information (X) in the mover information 406updated by the mover position calculation function 401. Next, the moverattitude calculation function 402 calculates attitude information (Y, Z,Wx, Wy, Wz), which is information on the attitude of each of the movers101, based on the values output from the identified Y-sensor 205 andZ-sensor 206 and updates the mover information 406. The moverinformation 406 updated by the mover attitude calculation function 402includes the mover position information (X) and the attitude information(Y, Z, Wx, Wy, Wz).

Next, the mover attitude control function 403 calculates applicationforce information 408 for each of the movers 101 from the current moverinformation 406 including the mover position information (X) and theattitude information (Y, Z, Wx, Wy, Wz) and an attitude target value.The application force information 408 is information on the magnitude offorce to be applied to each of the movers 101. The application forceinformation 408 includes information on three-axis force components (Tx,Ty, Tz) and three-axis moment components (Twx, Twy, Twz) of force T tobe applied described later. The application force information 408 isprepared for each mover 101 above the stator 201 as illustrated asTRQ-1, TRQ-2, . . . in FIG. 5, for example.

Next, the coil current calculation function 404 determines a currentinstruction value 409 applied to each coil 202 based on the applicationforce information 408 and the mover information 406.

In such a way, the integration controller 301 determines the currentinstruction value 409 by performing a process using the mover positioncalculation function 401, the mover attitude calculation function 402,the mover attitude control function 403, and the coil currentcalculation function 404. The integration controller 301 transmits thedetermined current instruction value 409 to the coil controllers 302.

The process performed by the mover position calculation function 401will now be described by using FIG. 6. FIG. 6 is a schematic diagramillustrating a process according to the mover position calculationfunction.

In FIG. 6, the reference point Oe is the position reference of thestator 201 to which the linear encoder 204 is attached. Further, thereference point Os is the position reference of the linear scale 104attached to the mover 101. FIG. 6 illustrates a case where two movers101 a and 101 b as the movers 101 are transported and three linearencoders 204 a, 204 b, and 204 c are arranged as the linear encoders204. Note that the linear scale 104 is attached in parallel to theX-direction at the same position as each of the movers 101 a and 101 b.

For example, one linear encoder 204 c faces the linear scale 104 of themover 101 b illustrated in FIG. 6. The linear encoder 204 c reads thelinear scale 104 of the mover 101 b and outputs a distance Pc. Further,the position of the linear encoder 204 c on the X-axis whose origin isthe reference point Oe is denoted as Sc. Therefore, the position Pos(101b) of the mover 101 b can be calculated by Equation (1) below.Pos(101b)=Sc−Pc  Equation (1)

For example, two linear encoders 204 a and 204 b face the linear scale104 of the mover 101 a illustrated in FIG. 6. The linear encoder 204 areads the linear scale 104 of the mover 101 a and outputs a distance Pa.Further, the position of the linear encoder 204 a on the X-axis whoseorigin is the reference point Oe is denoted as Sa. Therefore, theposition Pos(101 a) on the X-axis of the mover 101 a based on the outputof the linear encoder 204 a can be calculated by Equation (2) below.Pos(101a)=Sa−Pa  Equation (2)

Further, the linear encoder 204 b reads the linear scale 104 of themover 101 b and outputs a distance Pb. Further, the position of thelinear encoder 204 b on the X-axis whose origin is the reference pointOe is denoted as Sb. Therefore, the position Pos(101 a)′ on the X-axisof the mover 101 a based on the output of the linear encoder 204 b canbe calculated by Equation (3) below.Pos(101a)′=Sb−Pb  Equation (3)

Here, since each of the positions of the linear encoders 204 a and 204 bhas been measured accurately in advance, the difference between twovalues Pos(101 a) and Pos(101 a)′ is sufficiently small. When thedifference in position on the X-axis of the mover 101 based on theoutput of the two linear encoders 204 is sufficiently small in such away, these two linear encoders 204 can determine that the linear scale104 of the same mover 101 is observed.

Note that, when the plurality of linear encoders 204 face the same mover101, the position of the observed mover 101 can be uniquely determinedby calculating an averaged value of positions based on the output of theplurality of linear encoders 204 or the like.

The mover position calculation function 401 calculates and determinesthe position X in the X-direction of the mover 101 as mover positioninformation based on the output of the linear encoder 204 as describedabove.

Next, the process by the mover attitude calculation function 402 will bedescribed by using FIG. 7, FIG. 8A, and FIG. 8B.

FIG. 7 illustrates a case where the mover 101 c as the mover 101 istransported and the Y-sensors 205 a and 205 b as the Y-sensors 205 arearranged. The two Y-sensors 205 a and 205 b face the Y-target 105 of themover 101 c illustrated in FIG. 7. When the relative distance valuesoutput by the two Y-sensors 205 a and 205 b are denoted as Ya and Yb,respectively, and the interval between the Y-sensors 205 a and 205 b isdenoted as Ly, the rotation amount Wz around the Z-axis of the mover 101c is calculated by Equation (4) below.Wz=(Ya−Yb)/Ly  Equation (4)

Note that three or more Y-sensors 205 may face the Y-target 105 for aparticular position of the mover 101. In such a case, the slope of theY-target 105, that is, the rotation amount Wz around the Z-axis can becalculated by using a least-squares method.

Further, in FIG. 8A and FIG. 8B illustrate a case where the mover 101 das the mover 101 is transported and the Z-sensors 206 a, 206 b, and 206c are arranged as the Z-sensors 206. Three Z-sensors 206 a, 206 b, and206 c face the Z-target 106 of the mover 101 d illustrated in FIG. 8Aand FIG. 8B. Here, the relative distance values output by threeZ-sensors 206 a, 206 b, and 206 c are denoted as Za, Zb, and Zc,respectively. Further, the distance between sensors in the X-direction,that is, the distance between the Z-sensors 206 a and 206 b is denotedas Lz1. Further, the distance between sensors in the Y-direction, thatis, the distance between the Z-sensors 206 a and 206 c is denoted asLz2. Then, the rotation amount Wy around the Y-axis and the rotationamount Wx around the X-axis can be calculated by Equations (5a) and (5b)below, respectively.Wy=(Zb−Za)/Lz1  Equation (5a)Wx=(Zc−Za)/Lz2  Equation (5b)

The mover attitude calculation function 402 can calculate the rotationamounts Wx, Wy, and Wz around respective axes as the attitudeinformation on the mover 101, as described above.

Further, the mover attitude calculation function 402 can calculate theposition Yin the Y-direction and the position Z in the Z-direction ofthe mover 101 as the attitude information on the mover 101 in thefollowing manner.

First, calculation of the position Yin the Y-direction of the mover 101will be described by using FIG. 7. In FIG. 7, two Y-sensors 205 coveredby the mover 101 c are the Y-sensor 205 a and 205 b, respectively.Further, the measurement values of the Y-sensors 205 a and 205 b aredenoted as Ya and Yb, respectively. Further, the midpoint of theposition of the Y-sensor 205 a and the position of the Y-sensor 205 b isdenoted as denoted as Oe′. Moreover, the position of the mover 101 cobtained by Equations (1) to (3) is denoted as Os′, and the distancefrom Oe′ to Os' is denoted as dX′. At this time, the position Yin theY-direction of the mover 101 c can be calculated by approximation usingthe following equation.Y=(Ya+Yb)/2−Wz*dX′

Next, calculation of the position Z in the Z-direction of the mover 101will be described by using FIG. 8A and FIG. 8B. Three Z-sensors 206covered by the mover 101 d are denoted as the Z-sensors 206 a, 206 b,and 206 c, respectively. Further, the measurement values of theZ-sensors 206 a, 206 b, and 206 c are denoted as Za, Zb, and Zc,respectively. Further, the X-coordinate of the Z-sensor 206 a and theX-coordinate of the Z-sensor 206 c are the same. Further, the linearencoder 204 is located in the middle of the Z-sensor 206 a and theZ-sensor 206 c. Further, the position X of the Z-sensor 206 a and theZ-sensor 206 c is denoted as Oe′. Moreover, the distance from Oe″ to thecenter Os″ of the mover 101 is denoted as dX″. At this time, theposition Z in the Z-direction of the mover 101 can be calculated byapproximation using the following equation.Z=(Za+Zb)/2−Wy*dX″

Note that, when both the position Y and the position Z have largerotation amounts of Wz and Wy, respectively, the accuracy ofapproximation can be further increased for calculation.

Next, the process by the coil current calculation function 404 will bedescribed by using FIG. 1A and FIG. 1B. Note that, in denotation offorce used below, directions in which force in the X-direction, force inthe Y-direction, and force in the Z-direction are denoted as x, y, andz, respectively, the R-side that is the positive (+) Y-side is denotedas R, the L-side that is the negative (−) Y-side is denoted as L, thepositive (+) X-side is denoted as f, and the negative (−) X-direction isdenoted as b in FIG. 1A and FIG. 1B.

Force components working on the permanent magnets 103 on the R-side andthe L-side in FIG. 1A and FIG. 1B are expressed as below, respectively.Force working on each permanent magnet 103 is electromagnetic forcereceived by the permanent magnet 103 from a plurality of coils 202 towhich a current is applied. The permanent magnet 103 receives, from theplurality of coils 202 to which a current is applied, electromagneticforce in the X-direction that is the transport direction of the mover101 and, in addition, electromagnetic force in the Y-direction and theZ-direction that are different from the X-direction.

Each force working on the permanent magnet 103 on the R-side is asbelow.

FzfR: force working in the Z-direction of the permanent magnet 103 aR onthe R-side

FxfR: force working in the X-direction of the permanent magnet 103 bR onthe R-side

FyfR: force working in the Y-direction of the permanent magnet 103 bR onthe R-side

FxbR: force working in the X-direction of the permanent magnet 103 cR onthe R-side

FybR: force working in the Y-direction of the permanent magnet 103 cR onthe R-side

FzbR: force working in the Z-direction of the permanent magnet 103 dR onthe R-side

Each force working on the permanent magnet 103 on the L-side is asbelow.

FzfL: force working in the Z-direction of the permanent magnet 103 aL onthe L-side

FxfL: force working in the X-direction of the permanent magnet 103 bL onthe L-side

FyfL: force working in the Y-direction of the permanent magnet 103 bL onthe L-side

FxbL: force working in the X-direction of the permanent magnet 103 cL onthe L-side

FybL: force working in the Y-direction of the permanent magnet 103 cL onthe L-side

FzbL: force working in the Z-direction of the permanent magnet 103 dL onthe L-side

Further, the force T applied to the mover 101 is expressed by Equation(6) below. Note that values Tx, Ty, and Tz are three-axis forcecomponents, which are an X-direction component, a Y-direction component,and a Z-direction component of the force, respectively. Further, valuesTwx, Twy, and Twz are three-axis moment components, which are acomponent around the X-axis, a component around the Y-axis, and acomponent around the Z-axis of moment, respectively. The transportsystem 1 according to the present embodiment controls transportation ofthe mover 101 while controlling the attitude of the mover 101 withrespect to six axes by controlling these six-axis components of theforce T (Tx, Ty, Tz, Twx, Twy, Twz).T=(Tx,Ty,Tz,Twx,Twy,Twz)  Equation (6)

Accordingly, the values Tx, Ty, Tz, Twx, Twy, and Twz are calculated byEquations (7a), (7b), (7c), (7d), (7e), and (7f) below, respectively.Tx=FxfR+FxbR+FxfL+FxbL  Equation (7a)Ty=FyfL+FyfR+FybL+FybR  Equation (7b)Tz=FzbR+FzbL+FzfR+FzfL  Equation (7c)Twx={(FzfL+FzbL)−(FzfR+FzbR)}*rx  Equation (7d)Twy={(FzfL+FzfR)−(FzbL+FzbR)}*ry  Equation (7e)Twz={(FyfL+FyfR)−(FybL+FybR)}*rz  Equation (7f)

At this time, restrictions expressed by Equations (7g), (7h), (7i), and(7j) below can be introduced for force working on the permanent magnet103. By introducing these restrictions, it is possible to uniquelydetermine a combination of force components working on respectivepermanent magnets 103 to obtain the force T having predeterminedsix-axis components.FxfR=FxbR=FxfL=FxbL  Equation (7g)FyfL=FyfR  Equation (7h)FybL=FybR  Equation (7i)FzbR=FzbL  Equation (7j)

Next, a method by which the coil current calculation function 404determines a current amount applied to each coil 202 from force workingon each permanent magnet 103 will be described.

First, a case where force in the Z-direction is applied to the permanentmagnets 103 a and 103 d where polarities of N-pole and S-pole arealigned alternatingly in the Z-direction will be described. Note thatthe coils 202 are arranged such that the centers thereof in theZ-direction are located at the centers in the Z-direction of thepermanent magnets 103 a and 103 d. This causes substantially no forceworking in the X-direction and the Y-direction on the permanent magnets103 a and 103 d.

The value X denotes the position of the mover 101, the value j denotesthe number of one of the coils 202 aligned in a line, the magnitude offorce working in the Z-direction of the coil 202(j) per unit current isdenoted as Fz(j, X), and a current applied to the coil 202(j) is denotedas i(j). Note that the coil 202(j) is the j-th coil 202. In this case,the current i(j) can be determined to satisfy Equation (8) below. Notethat Equation (8) below is an equation for the permanent magnet 103 dR.Each current to be applied to the coil 202 can be determined for otherpermanent magnets 103 aR, 103 aL, and 103 dL in the same manner.ΣFz(j,X)*i(j)=FzbR  Equation (8)

The coil current calculation function 404 can determine a currentinstruction value to be applied to the coil 202(j) as described above.The mover 101 obtains levitation force to levitate in the Z-direction,and the attitude thereof is controlled by the force in the Z-directionapplied to the mover 101 in accordance with the current instructionvalue determined in such a way.

Note that, when the plurality of coils 202 apply force to the permanentmagnets 103, a current is divided with respect to the magnitude of forceper unit current in accordance with force applied by each coil 202, andthereby force working on the permanent magnet 103 can be uniquelydetermined.

Further, as illustrated in FIG. 1A, the permanent magnets 103 arearranged symmetrically on the L-side and the R-side of the mover 101.With such symmetry arrangement of the permanent magnets 103, it ispossible to use the force on the L-side and the R-side to cancelmultiple force components working on the permanent magnets 103, forexample, the force of Wx working on the permanent magnets 103 a and 103d, that is, the moment component around the X-axis. As a result, thisenables more accurate control of the attitude of the mover 101.

Next, a method of applying force independently in the X-direction andthe Y-direction to the permanent magnet 103 b whose polarities ofN-pole, S-pole, and N-pole are aligned alternatingly in the X-directionwill be described. FIG. 9 is a schematic diagram illustrating a methodof applying force independently in the X-direction and the Y-directionto the permanent magnet 103 b. The coil current calculation function 404determines a current instruction value applied to the coil 202 in orderto apply force independently in the X-direction and the Y-direction tothe permanent magnet 103 b as below. Note that force can be appliedindependently in the X-direction and the Y-direction also to thepermanent magnet 103 c in the same manner as for the permanent magnet103 b.

The value X denotes the position of the mover 101, the value j denotesthe number of one of the coils 202 aligned in a line, and the magnitudesof force working in the X-direction and the Y-direction of the coil202(j) per unit current are denoted as Fx(j, X) and Fy(j, X),respectively. Further, a current value conducted in the coil 202(j) isdenoted as i(j). Note that the coil 202(j) is the j-th coil 202.

The diagram in the upper part of FIG. 9 is a view in which the X-axis isdefined horizontally, the Y-axis is defined vertically, and six coils202 facing the permanent magnet 103 bR are picked up for illustration.The diagram in the middle part of FIG. 9 is a view when the diagram inthe upper part of FIG. 9 is viewed from the Z-direction. Numbers jbetween 1 and 6 are provided to the coils 202 in the order of alignmentin the X-direction, and each of the coils 202 is identified below bydenoting one as the coil 202(1), for example.

As illustrated in diagrams in the upper part and the middle part of FIG.9, the coils 202 are arranged at a pitch of a distance L. On the otherhand, the permanent magnets 103 of the mover 101 are arranged at a pitchof a distance 3/2*L.

The graph in the lower part of FIG. 9 is a graph schematicallyillustrating the magnitudes of the force Fx in the X-direction and theforce Fy in the Y-direction occurring when a unit current is applied toeach of the coils 202 illustrated in the diagrams in the upper part andthe middle part of FIG. 9.

For simplified illustration, in FIG. 9, the origin Oc of the position inthe X-direction of the coils 202 is defined as the midpoint of the coil202(3) and the coil 202(4), and the center Om in the X-direction of thepermanent magnet 103 bR is defined as the origin. Thus, FIG. 9illustrates a case where Oc matches Om, that is, a case of X=0.

At this time, for example, the force per unit current working on thecoil 202(4) corresponds to the magnitudes of Fx(4, 0) in the X-directionand Fy(4, 0) in the Y-direction. Further, the force per unit currentworking on the coil 202(5) corresponds to the magnitudes of Fx(5, 0) inthe X-direction and Fy(5, 0) in the Y-direction.

Here, the current values applied to the coils 202(1) to 202(6) areassumed to be i(1) to i(6), respectively. Then, the magnitude FxfR offorce working in the X-direction and the magnitude FyfR of force workingin the Y-direction on the permanent magnet 103 bR are expressed byEquations (9) and (10) below in general, respectively.FxfR=Fx(1,X)*i(1)+Fx(2,X)*i(2)+Fx(3,X)*i(3)+Fx(4,X)*i(4)+Fx(5,X)*i(5)+Fx(6,X)*i(6)  Equation(9)FyfR=Fy(1,X)*i(1)+Fy(2,X)*i(2)+Fy(3,X)*i(3)+Fy(4,X)*i(4)+Fy(5,X)*i(5)+Fy(6,X)*i(6)  Equation(10)

By determining a current instruction value so that current values i(1)to i(6) satisfying Equations (9) and (10) described above are applied tothe coils 202(1) to 202(6), respectively, it is possible to apply forceindependently in the X-direction and the Y-direction to the permanentmagnet 103 bR. The coil current calculation function 404 can determine acurrent instruction value applied to the coil 202(j) as described abovein order to apply force independently in the X-direction and theY-direction to the permanent magnet 103.

For more simplified illustration, in the case illustrated in FIG. 9, aconsidered example is a case where only the coils 202(3), 202(4), and202(5) out of the coils 202(1) to 202(6) are used for the permanentmagnet 103 bR and further the current values of these three coils arecontrolled so that the sum thereof becomes zero. In the case of thisexample, the force FxfR working in the X-direction and the force FyfRworking in the Y-direction on the permanent magnet 103 bR arerepresented by Equations (11) and (12) below, respectively.FxfR=Fx(3,X)*i(3)+Fx(4,X)*i(4)+Fx(5,X)*i(5)  Equation (11)FyfR=Fy(3,X)*i(3)+Fy(4,X)*i(4)+Fy(5,X)*i(5)  Equation (12)

Further, the current values of the coils 202(1) to 202(6) are set so asto satisfy Equations (13) and (14) below.i(3)+i(4)+i(5)=0  Equation (13)i(1)=i(2)=i(6)=0  Equation (14)

Therefore, when the magnitudes of force (FxfR, FyfR) required for thepermanent magnet 103 bR are determined, the current values i(1), i(2),i(3), i(4), i(5), and i(6) are uniquely determined. The force is appliedin the X-direction and the Y-direction to the mover 101 in accordancewith the current instruction value determined in such a way. Byreceiving the force in the X-direction applied to the mover 101, themover 101 obtains propulsion force of motion in the X-direction andmoves in the X-direction. Further, the attitude of the mover 101 iscontrolled by the force in the X-direction and the Y-direction appliedto the mover 101 in accordance with the current instruction valuedetermined in such a way.

In such a way, the integration controller 301 controls respectivesix-axis components of the force applied to the mover 101 by controllingthe current applied to the plurality of coils 202.

Note that, when the center Oc of the coil 202 moves with respect to thecenter Om of the permanent magnet 103 bR due to transportation of themover 101, that is, when X≠0, the coil 202 corresponding to the positionafter the motion can be selected. Furthermore, the same calculation asdescribed above can be performed based on the force per unit currentoccurring in the coil 202.

As described above, the integration controller 301 controls contactlesstransportation of the mover 101 above the stator 201 while controllingthe attitude of the mover 101 above the stator 201 with respect to sixaxes by controlling determining a current instruction value of a currentapplied to the plurality of coils 202. That is, the integrationcontroller 301 functions as a transport control unit that controlstransportation of the mover 101 and controls contactless transportationof the mover 101 above the stator 201 by controlling electromagneticforce received by the permanent magnet 103 from the plurality of coils202. Further, the integration controller 301 functions as an attitudecontrol unit that controls the attitude of the mover 101 and controlsthe attitude of the mover 101 above the stator 201 with respect to sixaxes. Note that all or a part of the function of the integrationcontroller 301 as a control apparatus may be replaced with the coilcontroller 302 or other control apparatuses.

As discussed above, according to the present embodiment, the six-axisforce of three-axis force components (Tx, Ty, Tz) and three-axis momentcomponents (Twx, Twy, Twz) can be applied to the mover 101 by using theplurality of coils 202 arranged in two lines. Thereby, it is possible tocontrol transport of the mover 101 while controlling the attitude of themover 101 with respect to six axes. According to the present embodiment,it is possible to control transport of the mover 101 while controllingthe attitude of the mover 101 with respect to six axes by using twolines of the coils 202 where the number of lines is smaller than thenumber of six-axis components of force that are variables to becontrolled.

Therefore, according to the present embodiment, since the number oflines of the coils 202 can be smaller, the mover 101 can be transportedcontactlessly while the attitude of the mover 101 is controlled withoutinvolving an increase in size or an increase in complexity of thesystem. Furthermore, according to the present embodiment, since thenumber of lines of the coils 202 can be smaller, an inexpensive andcompact magnetic levitation type transport system can be configured.

Further, according to the present embodiment, since the permanentmagnets 103 are arranged on the side face of the mover 101, good accessto the workpiece 102 can be realized. Thereby, it is possible to performa processing operation on the workpiece 102 on the mover 101 by using aprocess apparatus with great flexibility.

Second Embodiment

A second embodiment of the present invention will be described by usingFIG. 10 and FIG. 11. FIG. 10 is a schematic diagram illustrating themover 101 according to the present embodiment. FIG. 11 is a schematicdiagram illustrating the mover 101 and the stator 201 according to thepresent embodiment. Note that components similar to those in the firstembodiment described above are labeled with the same references, and thedescription thereof will be omitted or simplified.

The basic configuration of the mover 101 according to the presentembodiment is substantially the same as the configuration according tothe first embodiment. The mover 101 according to the present embodimentis different from the configuration according to the first embodiment inthe attachment form of the permanent magnets 103.

FIG. 10 is a diagram of the mover 101 according to the presentembodiment when viewed from the Y-direction. FIG. 10 illustrates thearrangement of the permanent magnet 103 on the side face on the R-sideof the mover 101 according to the present embodiment.

As illustrated in FIG. 10, unlike the first embodiment illustrated inFIG. 1B, the permanent magnets 103 bR and 103 cR are attached to themover 101 according to the present embodiment at positions distant fromthe center of the mover 101 by a distance rx2 in the Z-direction,respectively. The permanent magnet 103 b is attached at a positiondistant from the center of the mover 101 by a distance rx2 on the bottomside of the mover 101. On the other hand, the permanent magnet 103 c isattached at a position distant from the center of the mover 101 by adistance rx2 on the top side of the mover 101.

FIG. 11 is a diagram of the mover 101 and the stator 201 according tothe present embodiment when viewed from the X-direction. The left halfof FIG. 11 represents a cross section (A) taken along a line (A)-(A) ofFIG. 10. The right half of FIG. 11 represents a cross section (B) takenalong a line (B)-(B) of FIG. 10.

As illustrated in FIG. 11, in the mover 101 according to the presentembodiment, the permanent magnets 103 are attached to the one side face,specifically, only the side face on the R-side of the mover 101 unlikethe case of the first embodiment illustrated in FIG. 2.

Unlike the case of the first embodiment where the plurality of coils 202are aligned in two lines, the plurality of coils 202 are aligned in aline parallel to the X-direction in the stator 201 according to thepresent embodiment in association with the arrangement where thepermanent magnets 103 are attached on only one side face of the mover101. That is, the plurality of coils 202 are arranged and attached to bein a line parallel to the X-direction so as to be able to face thepermanent magnets 103 aR, 103 bR, 103 cR, and 103 dR on the side face onthe R-side, namely, one side of the mover 101 in the stator 201according to the present embodiment.

In the case of the mover 101 according to the present embodiment,respective components indicated in Equation (6) of the force T appliedto the mover 101 are expressed by Equations (15a), (15b), (15c), (15d),(15e), and (15f) below.Tx=FxfR+FxbR  Equation (15a)Ty=FyfR+FybR  Equation (15b)Tz=FzbR+FzfR  Equation (15c)Twx=(FybR−FyfR)*rx2  Equation (15d)Twy=(FzfR−FzbR)*ry  Equation (15e)Twz=(FyfR−FybR)*rz  Equation (15f)

Therefore, even when the permanent magnets 103 are arranged on theR-side, namely, only one side, the six-axis force of the three-axisforce components (Tx, Ty, Tz) and the three-axis moment components (Twx,Twy, Twz) can be applied to the mover 101 by using the plurality ofcoils 202 arranged in a line.

As described above, according to the present embodiment, the six-axisforce of three-axis force components (Tx, Ty, Tz) and three-axis momentcomponents (Twx, Twy, Twz) can be applied to the mover 101 by using theplurality of coils 202 arranged in a single line. Thereby, it ispossible to control transport of the mover 101 while controlling theattitude of the mover 101 with respect to six axes. According to thepresent embodiment, it is possible to control transport of the mover 101while controlling the attitude of the mover 101 with respect to six axesby using a single line of the coils 202 where the number of lines issmaller than the number of six-axis components of force that arevariables to be controlled.

Therefore, according to the present embodiment, since the number oflines of the coils 202 can be smaller, the mover 101 can be transportedcontactlessly while the attitude of the mover 101 is controlled withoutinvolving an increase in size or an increase in complexity of thesystem. Furthermore, according to the present embodiment, since thenumber of lines of the coils 202 can be smaller, a more inexpensive andcompact magnetic levitation type transport system can be configured.

Note that, while the case where the permanent magnets 103 are arrangedon the R-side, namely, only one side of the side faces on the R-side andthe L-side has been described above, the invention is not limitedthereto. Contrary to the case described above, the permanent magnets 103may be arranged on the L-side, namely, only one side of the side faceson the R-side and the L-side.

Third Embodiment

A third embodiment of the present invention will be described by usingFIG. 12 and FIG. 13. FIG. 12 is a schematic diagram illustrating themover 101 and the stator 201 according to the present embodiment. FIG.13 is a schematic diagram illustrating the mover 101 according to thepresent embodiment. Note that components similar to those in the firstand second embodiments described above are labeled with the samereferences, and the description thereof will be omitted or simplified.

The basic configuration of the mover 101 according to the presentembodiment is substantially the same as the configuration according tothe first embodiment. The mover 101 according to the present embodimentis different from the configuration according to the first and secondembodiments in the attachment form of the permanent magnets 103.

FIG. 12 is a diagram of the mover 101 and the stator 201 according tothe present embodiment when viewed from the X-direction. As illustratedin FIG. 12, unlike the first embodiment illustrated in FIG. 2, thepermanent magnets 103 are arranged and attached on the top face parallelto the X-direction of the mover 101 in the present embodiment. Thepermanent magnet 103 is attached to the yoke 107 provided on the topface of the mover 101.

FIG. 13 is a diagram of the mover 101 according to the presentembodiment when viewed from the Z-direction. FIG. 13 illustrates thearrangement of the permanent magnets 103 on the top view of the mover101 according to the present embodiment.

As illustrated in FIG. 13, the permanent magnets 103 aR, 103 bR, 103 cR,and 103 dR are arranged in portions on the R-side on the top face of themover 101. The permanent magnets 103 aR, 103 bR, 103 cR, and 103 dR arearranged at positions distant, from the origin O, which is the center ofthe mover 101, by a distance rx3 on the R-side in the Y-direction,respectively.

Further, the permanent magnets 103 aL, 103 bL, 103 cL, and 103 dL arearranged in portions on the L-side on the top face of the mover 101. Thepermanent magnets 103 aL, 103 bL, 103 cL, and 103 dL are arranged atpositions distant from the origin O by the distance rx3 on the L-side inthe Y-direction.

The permanent magnets 103 aR, 103 bR, 103 cR, and 103 dR are arranged insubstantially the same manner as the arrangement on the side face on theR-side of the mover 101 according to the first embodiment at portions onthe R-side on the top face of the mover 101. Further, the permanentmagnets 103 aL, 103 bL, 103 cL, and 103 dL are arranged in substantiallythe same manner as the arrangement on the side face on the L-side of themover 101 according to the first embodiment in portions on the L-side onthe top face of the mover 101.

The permanent magnets 103 a and 103 d are attached at positions distantfrom the origin O by a distance rz3 on one side and the other side inthe X-direction, respectively. The permanent magnets 103 c and 103 b areattached at positions distant from the origin O by a distance ry3 on oneside and the other side in the X-direction, respectively.

On the top face of the mover 101, the center portion between the R-sideportion and the L-side portion in which the permanent magnets 103 arearranged as described above serves as a portion on which the workpiece102 to be transported is placed.

On the other hand, as illustrated in FIG. 12, the plurality of coils 202are attached to the stator 201 so as to be located above the top face ofthe mover 101. The plurality of coils 202 are arranged in two linesparallel to the X-direction so as to be able to face downward both thepermanent magnets 103 on the R-side and the L-side on the top face ofthe mover 101 and attached to the stator 201. The plurality of coils 202on the R-side are aligned in a line parallel to the X-direction so as tobe able to face downward the permanent magnets 103 aR, 103 bR, 103 cR,and 103 dR on the R-side of the mover 101. The plurality of coils 202 onthe L-side are arranged in a line parallel to the X-direction so as tobe able to face downward the permanent magnets 103 aL, 103 bL, 103 cL,and 103 dL on the L-side of the mover 101.

When the mover 101 according to the present embodiment, respectivecomponents indicated in Equation (6) of the force T applied to the mover101 are expressed by Equations (16a), (16b), (16c), (16d), (16e), and(16f) below.Tx=FxfR+FxbR+FxfL+FxbL  Equation (16a)Ty=FyfL+FyfR+FybL+FybR  Equation (16b)Tz=FzbR+FzbL+FzfR+FzfL  Equation (16c)Twx={(FzfL+FzbL)−(FzfR+FzbR)}*rx3  Equation (16d)Twy={(FzfL+FzfR)−(FzbL+FzbR)}*ry3  Equation (16e)Twz={(FybL+FybR)−(FyfL+FyfR)}*rz3  Equation (16f)

At this time, restrictions expressed by Equations (16g), (16h), (16i),and (16j) below can be introduced for force working on the permanentmagnet 103. By introducing these restrictions, it is possible touniquely determine a combination of force components working onrespective permanent magnets 103 to obtain the force T havingpredetermined six-axis components.FxfR=FxbR=FxfL=FxbL  Equation (16g)FyfL=FyfR  Equation (16h)FybL=FybR  Equation (16i)FzbR=FzbL  Equation (16j)

Therefore, even when the permanent magnets 103 are arranged on the topface, the six-axis force of the three-axis force components (Tx, Ty, Tz)and the three-axis moment components (Twx, Twy, Twz) can be applied tothe mover 101 by using the plurality of coils 202 arranged in two lines.

As described above, according to the present embodiment, the six-axisforce of three-axis force components (Tx, Ty, Tz) and three-axis momentcomponents (Twx, Twy, Twz) can be applied to the mover 101 by using theplurality of coils 202 arranged in two lines. Thereby, it is possible tocontrol transport of the mover 101 while controlling the attitude of themover 101 with respect to six axes. According to the present embodiment,it is possible to control transport of the mover 101 while controllingthe attitude of the mover 101 with respect to six axes by using twolines of the coils 202 where the number of lines is smaller than thenumber of six-axis components of force that are variables to becontrolled.

Therefore, according to the present embodiment, since the number oflines of the coils 202 can be smaller, the mover 101 can be transportedcontactlessly while the attitude of the mover 101 is controlled withoutinvolving an increase in size or an increase in complexity of thesystem.

Further, in the present embodiment, the coils 202 can be further formedto include an iron core therein. This causes strong absorption force towork between the iron core of the coil 202 and the permanent magnet 103and thus contributes to levitate the mover 101. In particular, the coil202 including an iron core is preferable when the weight of the mover101 or the workpiece 102 placed on the mover 101 is large. Note that theiron core of the coil 202 may be any iron core as long as it causesattractive force with respect to at least any of the permanent magnets103 a, 103 b, 103 c, and 103 d.

Note that various modified examples are possible for the mover 101according to the third embodiment described above. The mover 101according to first to fourth modified examples of the third embodimentdescribed above will be described below.

First Modified Example

The mover 101 according to a first modified example will be described byusing FIG. 14A. FIG. 14A is a schematic diagram illustrating the mover101 according to the present modified example.

The basic configuration of the mover 101 according to the presentmodified example is substantially the same as that of the thirdembodiment illustrated in FIG. 12 and FIG. 13 described above. The mover101 according to the present modified example is different from theconfiguration according to the third embodiment in the form ofattachment of the permanent magnets 103.

FIG. 14A is a diagram of the mover 101 according to the present modifiedexample when viewed from the Z-direction. FIG. 14A illustrates thearrangement of the permanent magnets 103 on the top face of the mover101 according to the present modified example.

As illustrated in FIG. 14A, the permanent magnets 103 bR, 103 cR, and103 eR are arranged in the portions on the R-side on the top face of themover 101. The permanent magnets 103 bR, 103 cR, and 103 eR are arrangedat positions distant by the distance rx3 on the R-side in theY-direction from the center line in the X-direction running through theorigin O, which is the center of the mover 101, respectively.

Further, the permanent magnets 103 bL, 103 cL, and 103 eL are arrangedin the portions on the L-side on the top face of the mover 101. Thepermanent magnets 103 bL, 103 cL, and 103 eL are arranged at positionsdistant by the distance rx3 on the L-side in the Y-direction from thecenter line in the X-direction running through the origin O,respectively.

The permanent magnets 103 bR and 103 cR are arranged in substantiallythe same manner as the arrangement on the top face on the R-side of themover 101 according to the third embodiment illustrated in FIG. 13 inthe portions on the R-side on the top face of the mover 101. Further,the permanent magnets 103 bL and 103 cL are arranged in substantiallythe same manner as the arrangement on the top face on the L-side of themover 101 according to the third embodiment illustrated in FIG. 13 inthe portions on the L-side on the top face of the mover 101.

In the present modified example, without the permanent magnets 103 aR,103 dR, 103 aL, and 103 dL illustrated in FIG. 13 being arranged,instead, the permanent magnet 103 eR is arranged between the permanentmagnets 103 bR and 103 cR. Further, in the present modified example, thepermanent magnet 103 eL is arranged between the permanent magnets 103 bLand 103 cL. These features make the present modified example differentfrom the third embodiment illustrated in FIG. 13. The arrangement of themagnets of the permanent magnets 103 eR and 103 eL is similar to that ofthe permanent magnets 103 aR and 103 aL, respectively.

When the mover 101 according to the present modified example, respectivecomponents indicated in Equation (6) of the force T applied to the mover101 are expressed by Equations (17a), (17b), (17c), (17d), (17e), and(17f) below.Tx=FxfL+FxbL+FxfR+FxbR  Equation (17a)Ty=FycL+FycR  Equation (17b)Tz=FzfL+FzbL+FzfR+FzbR  Equation (17c)Twx={(FzfL+FzbL)−(FzfR+FzbR)}*rx3  Equation (17d)Twy={(FzfL+FzfR)−(FzbL+FzbR)}*ry3  Equation (17e)Twz={(FxfR+FxbR)−(FxfL+FxbL)}*rx3  Equation (17f)

According to the present modified example, the number of the permanentmagnets 103 arranged on the mover 101 can be reduced. Note that, whileforce in the Z-direction is unable to be controlled in the permanentmagnets 103 eR and 103 eL illustrated in FIG. 14A, it is possible toimprove controllability toward the Z-direction by increasing the numberof permanent magnets aligned and arranged in the X-direction.

Second Modified Example

The mover 101 according to a second modified example will be describedby using FIG. 14B. FIG. 14B is schematic diagram illustrating the mover101 according to the present modified example.

The basic configuration of the mover 101 according to the presentmodified example is substantially the same as the configuration of themover 101 according to the first modified example illustrated in FIG.14A described above. The mover 101 according to the present modifiedexample is different from the configuration of the first modifiedexample in that one of the permanent magnets 103 eR and 103 eL is notarranged.

FIG. 14B is a diagram of the mover 101 according to the present modifiedexample when viewed from the Z-direction. FIG. 14B illustrates thearrangement of the permanent magnets 103 on the top face of the mover101 according to the present modified example.

As illustrated in FIG. 14B, in the present modified example, thepermanent magnets 103 eL is arranged between the permanent magnets 103bL and 103 cL in the same manner as the first modified example. On theother hand, in the present modified example, unlike the first modifiedexample, the permanent magnet 103 eR is not arranged between thepermanent magnets 103 bR and 103 cR.

As discussed above, in the present modified example, only the permanentmagnet 103 eL of the permanent magnets 103 eR and 103 eL according tothe first modified example is arranged. Note that, unlike the caseillustrated in FIG. 14B, only the permanent magnet 103 eR of thepermanent magnets 103 eR and 103 eL may be arranged.

When the mover 101 according to the present modified example, respectivecomponents indicated in Equation (6) of the force T applied to the mover101 are expressed by Equations (17a), (17c), (17d), (17e), and (17f)described above except for the Y-direction force component Ty. In thecase of the present modified example, the Y-direction force component Tyis expressed by Equation (18b) below.Ty=FycL  Equation (18b)

According to the present modified example, the number of permanentmagnets 103 arranged on the mover 101 can be further reduced compared tothe first modified example. Also in the present modified example, bycontrolling Ty and Twz, it is possible to control six-axis components offorce including the Y-direction.

Third Modified Example

The mover 101 according to a third modified example will be described byusing FIG. 14C. FIG. 14C is a schematic diagram illustrating the mover101 according to the present modified example.

The basic configuration of the mover 101 according to the presentmodified example is substantially the same as that of the thirdembodiment illustrated in FIG. 12 and FIG. 13 described above. The mover101 according to the present modified example is different from theconfiguration according to the third embodiment in the form ofattachment of the permanent magnets 103.

FIG. 14C is a diagram of the mover 101 according to the present modifiedexample when viewed from the Z-direction. FIG. 14C illustrates thearrangement of the permanent magnets 103 on the top face of the mover101 according to the present modified example.

As illustrated in FIG. 14C, the permanent magnets 103 bR, 103 cR, and103 dR are arranged in the portions on the R-side on the top face of themover 101. The permanent magnets 103 bR, 103 cR, and 103 dR are arrangedat positions distant by the distance rx3 on the R-side in theY-direction from the center line in the X-direction running through theorigin O, which is the center of the mover 101, respectively.

Further, the permanent magnets 103 aL, 103 bL, and 103 cL are arrangedin the portions on the L-side on the top face of the mover 101. Thepermanent magnets 103 aL, 103 bL, and 103 cL are arranged at positionsdistant by the distance rx3 on the L-side in the Y-direction from thecenter line in the X-direction running through the origin O,respectively.

The permanent magnets 103 bR, 103 cR, and 103 dR are arranged insubstantially the same manner as the arrangement on the top face on theR-side of the mover 101 according to the third embodiment illustrated inFIG. 13 in the portions on the R-side on the top face of the mover 101.In the present modified example, unlike the third embodiment illustratedin FIG. 13, the permanent magnet 103 aR is not arranged.

Further, the permanent magnets 103 aL, 103 bL, and 103 cL are arrangedin substantially the same manner as the arrangement on the top face onthe L-side of the mover 101 according to the third embodimentillustrated in FIG. 13 in the portions on the L-side on the top face ofthe mover 101. In the present modified example, unlike the thirdembodiment illustrated in FIG. 13, the permanent magnet 103 dL is notarranged.

Note that, in contrast to the present modified example, the permanentmagnets 103 aR and 103 dL may be arranged, and the permanent magnets 103dR and 103 aL may not be arranged.

In the second modified example described above, when the mover 101passes through a region where no coil 202 can be arranged so as to facethe permanent magnets 103 eL, a situation where the Y-direction forcecomponent Ty cannot be applied may occur. In contrast, in the presentmodified example, with the coils 202 being arranged so as to face atleast any one of the permanent magnets 103 dR and 103 aL, theY-direction force component Ty can be applied. Thereby, in the presentmodified example, it is possible to control the six-axis components offorce including the Y-direction more reliably than in the secondmodified example. That is, the present modified example may be tolerantto a case where no force can be applied in the Y-direction in the secondmodified example.

When the mover 101 according to the present modified example, respectivecomponents indicated in Equation (6) of the force T applied to the mover101 are expressed by Equations (17a), (17c), (17d), and (17e) describedabove except for the Y-direction force component Ty and thearound-Z-axis moment component Twz. In the case of the present modifiedexample, the Y-direction force component Ty and the around-Z-axis momentcomponent Twz are expressed by Equations (19b-1) and (19f-1) orEquations (19b-2) and (19f-2) below in accordance with which of thepermanent magnet 103 dR or 103 aL faces the coil 202.

First, when the permanent magnet 103 dR does not face the coil 202 andthe permanent magnet 103 aL faces the coil 202, the Y-direction forcecomponent Ty and the around-Z-axis moment component Twz are expressed byEquations (19b-1) and (19f-1) below.Ty=FyfL  Equation (19b-1)Twz={(FxfR+FxbR)−(FxfL+FxbL)}*rx3−FyfL*rz3  Equation (19f-1)

On the other hand, when the permanent magnet 103 aL does not face thecoil 202 and the permanent magnet 103 dR faces the coil 202, theY-direction force component Ty and the around-Z-axis moment componentTwz are expressed by Equations (19b-2) and (19f-2) below.Ty=FybR  Equation (19b-2)Twz={(FxfR+FxbR)−(FxfL+FxbL)}*rx3+FybR*rz3  Equation (19f-2)

Note that, when the permanent magnets 103 aL and 103 dR face the coil202, the Y-direction force component Ty and the around-Z-axis momentcomponent Twz are expressed by Equations (19b-3) and (19f-3) below.Ty=FyfL+FybR  Equation (19b-3)Twz={(FxfR+FxbR)−(FxfL+FxbL)}*rx3+(FybR−FyfL)*rz3  Equation (19f-3)

Fourth Modified Example

The mover 101 according to a fourth modified example will be describedby using FIG. 14D. FIG. 14D is a schematic diagram illustrating themover 101 according to the present modified example.

The basic configuration of the mover 101 according to the presentmodified example is substantially the same as that of the thirdembodiment illustrated in FIG. 12 and FIG. 13 described above. The mover101 according to the present modified example is different from theconfiguration according to the third embodiment in the form ofattachment of the permanent magnets 103.

FIG. 14D is a diagram of the mover 101 according to the present modifiedexample when viewed from the Z-direction. FIG. 14D illustrates thearrangement of the permanent magnets 103 on the top face of the mover101 according to the present modified example.

As illustrated in FIG. 14D, the permanent magnets 103 bR and 103 cR arearranged in the portions on the R-side on the top face of the mover 101.The permanent magnets 103 bR and 103 cR are arranged at positionsdistant by the distance rx3 on the R-side in the Y-direction from thecenter line in the X-direction running through the origin O, which isthe center of the mover 101, respectively.

In the present modified example, a plurality of permanent magnets 103giR (where i=1, 2, 3, 4, 5) similar to the permanent magnets 103 aR arealigned and arranged at a constant interval in the X-direction outsidethe permanent magnets 103 bR and 103 cR in portions on the R-side on thetop face of the mover 101. A yoke 107 to which the plurality ofpermanent magnets 103 giR are attached is separated from a yoke 107 towhich the permanent magnets 103 bR and 103 cR are attached. Theplurality of permanent magnets 103 giR are not limited to the fiveillustrated in FIG. 14D, and the number of permanent magnets 103 giR maybe any number as long as it is plural.

Further, the permanent magnets 103 bL and 103 cL are arranged in theportions on the L-side on the top face of the mover 101. The permanentmagnets 103 bL and 103 cL are arranged at positions distant by thedistance rx3 on the L-side in the Y-direction from the center line inthe X-direction running through the origin O, respectively.

In the present modified example, a plurality of permanent magnets 103giL (where i=1, 2, 3, 4, 5) similar to the permanent magnets 103 aL arealigned and arranged at a constant interval in the X-direction outsidethe permanent magnets 103 bL and 103 cL in portions on the L-side on thetop face of the mover 101. A yoke 107 to which the plurality ofpermanent magnets 103 giL are attached is separated from a yoke 107 towhich the permanent magnets 103 bL and 103 cL are attached. Theplurality of permanent magnets 103 giL are not limited to the fiveillustrated in FIG. 14D, and the number of permanent magnets 103 giL maybe any number as long as it is plural.

As discussed above, the yoke 107 to which the permanent magnets 103 aand 103 d formed of a group of magnets in which permanent magnets arealigned in the Y-direction are attached is separated from the yoke 107to which the permanent magnets 103 b and 103 c formed of a group ofmagnets in which permanent magnets are aligned in the X-direction areattached. Thereby, unnecessary interference of the magnetic flux can bereduced or prevented, and controllability can be improved. However, theyokes 107 may be integrally formed without being separated. In such acase, the mover 101 can be configured with low cost compared to the casewhere the yokes 107 are separated.

Note that, also in the case of the third embodiment illustrated in FIG.13, the yokes 107 to which the permanent magnets 103 formed of a groupof magnets in which permanent magnets are aligned in directionsdifferent from each other are attached may be separated from each otherin the same manner as in the present modified example. In such a case,the yoke 107 to which the permanent magnets 103 a and 103 d formed of agroup of magnets in which permanent magnets are aligned in theY-direction are attached may be separated from the yoke 107 to which thepermanent magnets 103 b and 103 c formed of a group of magnets in whichpermanent magnets are aligned in the X-direction are attached.

Further, also in the first embodiment illustrated in FIG. 1B, the secondembodiment illustrated in FIG. 10, and the fourth embodiment illustratedin FIG. 15, the yokes 107 to which the permanent magnets 103 formed of agroup of magnets in which permanent magnets are aligned in directionsdifferent from each other are attached may be separated from each otherin the same manner as in the present modified example. In such a case,the yoke 107 to which the permanent magnets 103 a and 103 d formed of agroup of magnets in which permanent magnets are aligned in theZ-direction are attached may be separated from the yoke 107 to which thepermanent magnets 103 b and 103 c formed of a group of magnets in whichpermanent magnets are aligned in the X-direction are attached.

In the present modified example, the force working in the Y-direction ofthe permanent magnet 103 giR is denoted as FyiR, the force working inthe Y-direction of the permanent magnet 103 giL is denoted as FyiL, andthen the Y-direction force component Ty corresponds to the sum of forcecomponents working on respective permanent magnets 103 giR and 103 giL.That is, in the case of the mover 101 according to the present modifiedexample, the Y-direction force component Ty is expressed by Equation(20b) below.Ty=ΣFyiR+ΣFyiL  Equation (20b)

According to the present modified example, by adjusting the number ofthe permanent magnets 103 giR and 103 giL to be arranged, it is possibleto increase or decrease the Y-direction force component Ty.

Other Modified Examples

For the mover 101 according to the third embodiment described above,further other modified examples are possible. For example, to furtherenhance transportation capacity in the X-axis direction, the number ofpermanent magnets can be larger than that of magnets of the four sets ofthe permanent magnets 103 bR, 103 cR, 103 bL, and 103 cL. Specifically,many permanent magnets similar to the permanent magnet 103 bR can bealigned horizontally in one or more lines to portions on the R-side onthe top face of the mover 101. Similarly, many permanent magnets similarto the permanent magnet 103 bL can be aligned horizontally in one ormore lines to portions on the L-side on the top face of the mover 101.

Fourth Embodiment

A fourth embodiment of the present invention will be described by usingFIG. 15 and FIG. 16. FIG. 15 and FIG. 16 are schematic diagramsillustrating the mover 101 and the stator 201 according to the presentembodiment. Note that components similar to those in the first to thirdembodiments described above are labeled with the same references, andthe description thereof will be omitted or simplified.

The basic configuration of the mover 101 according to the presentembodiment is substantially the same as the configuration according tothe first embodiment. The mover 101 according to the present embodimentis different from the configuration according to the first to thirdembodiments in the form of attachment of the permanent magnets 103.

The diagram in the upper part of FIG. 15 is a view of the mover 101 andthe stator 201 according to the present embodiment when viewed from theZ+ side in the Z-direction. Note that, for simplified illustration, theworkpiece 102 is not illustrated in FIG. 15. The diagram in the middlepart of FIG. 15 is a view of the side face on the R-side of the mover101 according to the present embodiment when viewed from the R-side inthe Y-direction. The diagram in the lower part of FIG. 15 is a view ofthe side face on the L-side of the mover 101 according to the presentembodiment when viewed from the L-side in the Y-direction. Note that thediagram in the lower part of FIG. 15 illustrates the inverted view ofthe side face on the L-side of the mover 101 for better representation.

Further, FIG. 16 is a diagram of the mover 101 and the stator 201according to the present embodiment when viewed from the X-direction.The left part of FIG. 16 illustrates the sectional view (A) taken alongthe line (A)-(A) of the diagram in the middle part of FIG. 15. Further,the right part of FIG. 16 illustrates the sectional view (B) taken alongthe line (B)-(B) of the diagram in the middle part of FIG. 15.

As illustrated in FIG. 15, unlike the first embodiment, the permanentmagnets 103 cR and 103 dR are attached to the side face on the R-side ofthe mover 101. That is, in the present embodiment, the permanent magnets103 aR and 103 bR are not attached to the side face on the R-side of themover 101.

The permanent magnets 103 cR and 103 dR are attached to positionsdistant from the origin O by ry1 in the Y-direction, which is the centerof the mover 101, respectively. Further, the permanent magnet 103 dR isattached to a position distant from the origin O by rx1 on the otherside in the X-direction. Further, the permanent magnet 103 cR isattached to a position distant from the origin O by rx2 in the otherside in the X-direction.

Further, unlike the first embodiment, the permanent magnets 103 aL and103 bL are attached to the side face on the L-side of the mover 101.That is, in the present embodiment, the permanent magnets 103 cL and 103dL are not attached to the side face on the L-side of the mover 101.

The permanent magnets 103 aL and 103 bL are attached to positionsdistant from the origin O by ry1 in the Y-direction, respectively.Further, the permanent magnet 103 aL is attached to a position distantfrom the origin O by rx1 on one side in the X-direction. Further, thepermanent magnet 103 bL is attached to a position distant from theorigin O by rx2 in one side in the X-direction.

Furthermore, the permanent magnets 103 cR and 103 dR and the permanentmagnets 103 aL and 103 bL are attached to the mover 101 so that thepositions in the Z-direction are shifted in the Z-direction and arrangedso as to be different from each other. That is, the permanent magnet 103cR and 103 dR are attached to positions distant from the origin O by thedistance rz1 on the upper side of the mover 101 in the Z-direction,respectively. On the other hand, further, the permanent magnet 103 aLand 103 bL are attached to positions distant from the origin O by thedistance rz1 on the bottom side of the mover 101 in the Z-direction,respectively.

In such a way, in the present embodiment, the permanent magnets 103 areattached to the mover 101 such that the permanent magnets 103 areshifted and arranged asymmetrically in the Z-direction on the side faceson the R-side and the L-side.

The positions in the Z-direction of lines of the coils 202 are differentfor the R-side and the L-side as illustrated in FIG. 16 in the stator201 in association with the fact that positions in the Z-direction ofthe permanent magnets 103 are different from each other in the sidefaces on the R-side and the L-side of the mover 101 as described above.That is, the line of the coils 202R, which are the coils 202 on theR-side, is arranged in parallel to the X-direction so as to be able toface the permanent magnets 103 cR and 103 dR on the side face on theR-side of the mover 101. On the other hand, the line of the coils 202L,which are the coils 202 on the L-side, is arranged in parallel to theX-direction so as to be able to face the permanent magnets 103 aL and103 bL on the side face on the L-side of the mover 101.

In the case of the mover 101 according to the present embodiment,respective components indicated in Equation (6) of the force T appliedto the mover 101 are expressed by Equations (21a), (21b), (21c), (21d),(21e), and (21f) below.Tx=FxbR+FxfL  Equation (21a)Ty=FyfL+FybR  Equation (21b)Tz=FzbR+FzfL  Equation (21c)Twx=(FzfL−FzbR)*ry1+(FybR−FyfL)*rz1  Equation (21d)Twy=(FzfL−FzbR)*rx1  Equation (21e)Twz=(FybR−FyfL)*rx2  Equation (21f)

Therefore, even when the permanent magnets 103 are arrangedasymmetrically, the six-axis force of the three-axis force components(Tx, Ty, Tz) and the three-axis moment components (Twx, Twy, Twz) can beapplied to the mover 101 by using the plurality of coils 202 arranged intwo lines.

As described above, according to the present embodiment, the six-axisforce of three-axis force components (Tx, Ty, Tz) and three-axis forcecomponents (Twx, Twy, Twz) can be applied to the mover 101 by using theplurality of coils 202 arranged in two lines. Thereby, it is possible tocontrol transport of the mover 101 while controlling the attitude of themover 101 with respect to six axes. According to the present embodiment,it is possible to control transport of the mover 101 while controllingthe attitude of the mover 101 with respect to six axes by using twolines of the coils 202 where the number of lines is smaller than thenumber of six-axis components of force that are variables to becontrolled.

Therefore, according to the present embodiment, since the number oflines of the coils 202 can be smaller, it is possible to transport themover 101 contactlessly while controlling the attitude of the mover 101without involving an increase in size or an increase in complexity ofthe system.

Further, with the permanent magnets 103 being arranged symmetrically onthe mover 101 as with the present embodiment, six-axis control of theattitude of the mover 101 and transport control of the mover 101 can berealized by using a smaller number of permanent magnets 103 than in thefirst embodiment. Thus, according to the present embodiment, since notonly the number of lines of the coils 202 but also the number ofpermanent magnets 103 can be reduced, more inexpensive and compactmagnetic levitation type transport system can be configured.

OTHER EMBODIMENTS

The present invention is not limited to the embodiments described above,and various modifications are possible.

For example, in a case of use in a vacuum environment or an underwaterenvironment, an organic substance or the like is likely to scatter orflow out from a member such as plastic used around the coil 202 or in acore material. Further, an adhesive agent for insulation is likely topartially flow out or be further deteriorated in the same manner.

Thus, in particular, in a vacuum environment or an underwaterenvironment or in an environment with less dirt, such as a clean room,it is preferable to cover a coil or a component around the coil withsome component to insulate it from the surrounding environment. Thereare some methods of insulation, and it is preferable to cover one ormore coils with a metal box and introduce a gas therein, for example.

Furthermore, to dissipate or emit heat generated from a coil to theoutside, the gas is preferably a gas having a large thermalconductivity, preferably a helium gas, for example, or may be a hydrogengas. However, a nitrogen gas, a carbon dioxide gas, or an air may alsoprovide sufficient component protection performance.

Furthermore, one or more coils may be collectively aligned and enclosedin a box-like shape to form a coil box unit, and a coil line may beformed by aligning a plurality of coil box units. It is preferable toprovide a height reference or a position reference to the external ofeach coil box unit for easier operation to adjust the height or theposition to the same in order to align the box units.

Further, while the case where only electromagnetic force received by thepermanent magnets 103 from the coils 202 is utilized as levitation forceto levitate the mover 101 has been described as an example in the aboveembodiments, the invention is not limited thereto. For example, when theweight of the mover 101 or the weight of the workpiece 102 placed on themover 101 is large and the levitation force to be applied in thevertical direction is large, a static pressure of a fluid such as an airmay be separately used for levitation to aid the levitation force.

Further, while the case where a plurality of coils 202 are arranged intwo lines or one line has been described as an example in the aboveembodiment, the invention is not limited thereto. The plurality of coils202 can also be arranged in any of three lines, four lines, and fivelines, for example, in accordance with the plurality of permanentmagnets 103 arranged on the mover 101. According to the presentinvention, six-axis control of the attitude of the mover 101 can berealized by using lines of the coils 202 where the number of lines issmaller than six that is the number of variables in six-axis control ofthe attitude of the mover 101.

Further, the transport system according to the present invention can beused as a transport system that transports a workpiece together with amover to a working region of each process apparatus such as a machinetool that performs each working process on the workpiece that is to bean article in a manufacturing system that manufactures an article suchas an electronic component. The process apparatus that performs aworking process may be any apparatus such as an apparatus that performsassembling of components on a workpiece, an apparatus that performscoating or painting, or the like. Further, an article to be manufacturedis not particularly limited, and any article may be manufactured.

As described above, an article can be manufactured by using thetransport system according to the present invention to transport aworkpiece to a working region and performing a working process on theworkpiece transported in the working region. As described above, thetransport system according to the present invention involves neitherincrease in size nor increase in complexity of the system. Therefore, anarticle manufacturing system that employs the transport system accordingto the present invention for transportation of a workpiece can alsoprovide a significantly flexible layout of apparatuses that performrespective working processes without involving an increase in size or anincrease in complexity of the system. According to the presentinvention, it is possible to transport a mover contactlessly whilecontrolling the attitude of the mover without involving an increase insize of system arrangement.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2018-149579, filed Aug. 8, 2018, and Japanese Patent Application No.2018-231005, filed Dec. 10, 2018, which are hereby incorporated byreference herein in their entirety.

What is claimed is:
 1. A transport system comprising: a mover movable ina first direction, the mover having a first magnet group and a secondmagnet group, the first magnet group including a plurality of firstmagnets arranged along a first direction and the second magnet groupincluding a plurality of second magnets arranged along a seconddirection crossing the first direction; and a stator having a pluralityof coils, the plurality of coils being arranged along the firstdirection so as to be able to face the first magnet group and the secondmagnet group, wherein the second magnet group is provided on a tip sideof the mover than the first magnet group in the first direction.
 2. Thetransport system according to claim 1, wherein the second magnet groupincludes a plurality of second magnet groups, at least one of theplurality of second magnet groups is provided at the tip of the moverthan the first magnet group in the first direction, and at least anotherof the plurality of second magnet groups is provided at an end of themover than the first magnet group in the first direction.
 3. Thetransport system according to claim 1, wherein the first magnet groupincludes a plurality of first magnet groups, the second magnet groupincludes a plurality of second magnet groups, and at least one of theplurality of second magnet groups is provided between the two firstmagnet group.
 4. The transport system according to claim 3, whereinmagnetic poles of the first magnets closest to the second magnet groupincluded respectively in the two first magnet groups across the secondmagnet group are the same as each other.
 5. The transport systemaccording to claim 1, wherein the first magnet group and the secondmagnet group are provided with a space therebetween.
 6. The transportsystem according to claim 1, wherein a length of at least one coil ofthe plurality of coils in the second direction is shorter than a lengthof the second magnet group in the second direction.
 7. The transportsystem according to claim 1, wherein a length of at least one coil ofthe plurality of coils in the second direction is longer than a lengthof the first magnet group in the second direction.
 8. The transportsystem according to claim 1, wherein first magnets next to each other inthe first direction included in the plurality of first magnets havedifferent polarities from each other at a position where the pluralityof first magnets are able to face the plurality of coils, and whereinsecond magnets next to each other in the second direction included inthe plurality of second magnets have different polarities from eachother at a position where the plurality of second magnets are able toface the plurality of coils.
 9. The transport system according to claim1, wherein the mover has a top face parallel to the first direction, andwherein the first magnet group and the second magnet group are arrangedon the top face.
 10. The transport system according to claim 9, whereinat least one of the plurality of coils has an iron core and is arrangedto be able to face downward with respect to the first magnet group andthe second magnet group.
 11. A control method of controlling a transportsystem, the transport system comprising: a mover movable in a firstdirection, the mover having a first magnet group and a second magnetgroup, the first magnet group including a plurality of first magnetsarranged along a first direction and the second magnet group including aplurality of second magnets arranged along a second direction crossingthe first direction; and a stator having a plurality of coils, theplurality of coils being arranged along the first direction so as to beable to face the first magnet group and the second magnet group, whereinthe second magnet group is provided on a tip side of the mover than thefirst magnet group in the first direction, the control methodcomprising: controlling transportation of the mover in the firstdirection by controlling electromagnetic force generated between thefirst magnet group and the plurality of coils; and controlling anattitude of the mover by controlling electromagnetic force generatedbetween the first magnet magnetic group and the plurality of coilsand/or between the second magnet magnetic group and the plurality ofcoils.
 12. The control method according to claim 11, wherein the secondmagnet group includes a plurality of second magnet groups, at least oneof the plurality of second magnet groups is provided at the tip of themover than the first magnet group in the first direction, and at leastanother of the plurality of second magnet groups is provided at an endof the mover than the first magnet group in the first direction.
 13. Thecontrol method according to claim 11, wherein the first magnet group andthe second magnet group are provided with a space therebetween.
 14. Thecontrol method according to claim 11, wherein a length of at least onecoil of the plurality of coils in the second direction is shorter than alength of the second magnet group in the second direction.
 15. Thecontrol method according to claim 11, wherein a length of at least onecoil of the plurality of coils in the second direction is longer than alength of the first magnet group in the second direction.
 16. An articlemanufacturing method for manufacturing an article, the methodcomprising: transporting a workpiece by using the control methodaccording to claim 11; and performing, by using a process apparatus, aprocessing on the workpiece.